Kinetochores and chromatin diminution in early embryos of Parascaris univalens

In Parascaris the mitotic chromosomes of gonial germline cells are holocentric and possess a continuous kinetochore along their entire length. By contrast, in meiotic cells, the centromeric activity is restricted to the heterochromatic tips where direct insertion of spindle microtubules into chromat...

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Bibliographic Details
Published in:The Journal of cell biology 1992-07, Vol.118 (1), p.23-32
Main Authors: Goday, C. (Centro de Investigaciones Biologicas, Valazquez, Madrid, Spain), Gonzalez-Garcia, J.M, Esteban, M.R, Giovinazzo, G, Pimpinelli, S
Format: Article
Language:English
Subjects:
Anaphase
Animals
Biological and medical sciences
Cell Biology
Cell cycle, cell proliferation
Cell division
Cell physiology
Centromere - metabolism
Centromere - ultrastructure
Centromeres
Chromatin
Chromatin - metabolism
CHROMATINE
CHROMOSOME
Chromosomes
Chromosomes - ultrastructure
CROMATINA
CROMOSOMAS
DESARROLLO EMBRIONARIO
DEVELOPPEMENT EMBRYONNAIRE
Embryos
Euchromatin
Female
Fluorescent Antibody Technique
Fundamental and applied biological sciences. Psychology
Germ cells
Germ Cells - metabolism
Heterochromatin - metabolism
Kinetochores
Life Sciences & Biomedicine
MEIOSE
MEIOSIS
Metaphase
Microtubules
Microtubules - metabolism
MITOSE
MITOSIS
Mitosis - physiology
Mitotic spindle apparatus
Molecular and cellular biology
Nematoda - embryology
PARASCARIS
Science & Technology
Spindle Apparatus - metabolism
Tubulin - isolation & purification
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Summary:In Parascaris the mitotic chromosomes of gonial germline cells are holocentric and possess a continuous kinetochore along their entire length. By contrast, in meiotic cells, the centromeric activity is restricted to the heterochromatic tips where direct insertion of spindle microtubules into chromatin without any kinetochore plate is seen. In the presomatic cells of early embryos, which undergo heterochromatin elimination, only euchromatin shows kinetic activity. After developing a technique to separate the very resistant egg shell from the embryos, we studied the cell divisions during early embryogenesis by immunochemical and EM approaches. The results reported here show that in presomatic cells microtubules bind only the euchromatin where a continuous kinetochore plate is present. We also report observations suggesting that the binding of the long kinetochores to the mitotic spindle initiates to a limited number of sites and extends along the entire length, during chromosome condensation. The existence of different centromere stages in different cell types, rends Parascaris chromosomes a very good model to study centromere organization
ISSN:0021-9525
1540-8140
DOI:10.1083/jcb.118.1.23